Valve sends word that it has launched a giant holiday sale on Steam, offering 10-75% discounts on its entire stock of downloadable PC titles.

While new titles such as Grand Theft Auto IV and Call of Duty: World at War are only marked down 10%, some real bargains on recent games are out there: Left 4 Dead, Warhammer Online, Fallout 3, and Far Cry 2 are all marked down 20-25%.

Irresistible cheapness can also be found in massive price cuts to games like Portal ($5), Team Fortress 2 ($10), BioShock ($5) and the Dawn of War Everything Pack ($30). Games such as Company of Heroes, Titan Quest, Civilization IV and World of Goo can all be had for a mere $15.